19V load switch of main DC power toggles on and off continuously. Surprised to find that the charger IC Max8724 is missing.
MAX8724 replaced and 19V rail is stable. Attempt to power on results in fans spinning, but no display.
PLTRST signal found ok. Memory SPD signals on scope found OK, which means that the platform is executing the BIOS.
Next, I attached Diagnostic Post card, eager to know what this puppy throws a code. The post halts at code "4A". Downloaded and flashed new BIOS, but still the same result.
Searching the internet, post code " 4A" for Phoenix BIOS means "Video adaptor not initialized', this pointed at suspect at bad Nvidia graphics chip.
To confirm the suspicion, heated the die of graphics chip, keeping hot air setting at 220 DegC and 10 mm distance for like 5 mins..and we have success..
The board boots up fine and customer takes back the machine, because he can't afford a new graphics chip..or even a UMA conversion.
[ Post made via Android ]
[ Post made via Android ]
